I like to run all apps maximized. That way, I can focus on the task at hand and not be distracted by stuff going on in other apps. Also, less clutter = more productivity.
As a web developer. I always run two monitors - one has my emacs, terminals, process manager, and browser, all nicely tiled on a 30" monitor.
On my other screen, I keep iTunes, skype, and other distractions.
I think this is more a personal preference thing than anything else. (And I use my laptop for music and IM, but its usually displaying the Vista enter password screen anyway.)